Pronoun comprehension in individuals with Down syndrome: the role of age.

BACKGROUND A number of studies have suggested that language in individuals with Down syndrome (DS) may not be simply delayed compared with language in typically developing (TD) children, but deviant. The deviance has been detected in the comprehension of pronouns, and it has triggered proposals for the existence of a specific syntactic deficit in individuals with DS. However, the developmental path of pronoun comprehension in individuals with DS is unknown as there are no studies examining individuals of different ages. AIMS To perform a pilot study examining pronoun comprehension in adolescents and adults with DS in comparison with TD children. Research questions include: Are some pronoun types more difficult than others for each of the two groups (DS and TD)? Is there a difference in performance between the two groups? Does performance correlate with chronological age in the DS group? METHODS & PROCEDURES Using a manual picture selection task, we examined the comprehension of different types of pronouns in 14 Greek-speaking individuals with DS, ranging from 10 to 34 years of age. We also tested a control group of TD children as well as a typical adult group. The TD and DS groups were recruited and tested in pre-schools and schools/centres for individuals with learning disabilities, respectively. Within- and between-group comparisons were performed for all conditions. For the DS group, correlations between chronological age and performance in each condition were also explored. OUTCOMES & RESULTS Results reveal a significant positive correlation of age with performance in the DS group, but only in structures that also presented difficulties to TD children. Structures that presented difficulties only to individuals with DS do not appear to be less problematic for older participants. CONCLUSIONS & IMPLICATIONS These findings provide support to the deviance hypothesis by suggesting that the syntactic deficit in the comprehension of pronouns in individuals with DS is present in individuals of a wide age range. At the same time, the results, if corroborated by large-scale studies, suggest that some aspects of grammatical development in individuals with DS may continue even after adolescence and well into adulthood. We argue that these findings can contribute towards more targeted intervention practices by increasing our knowledge of the behavioural phenotype of DS.